There is provided an apparatus for determining a heart pulse of a person, the apparatus comprising at least two detectors configured to detect a blood pulse optically from the blood circulation of the person and to be placed optically on the skin of the person such that the detection of the blood pulse by each of the at least two detectors is expected to take place in a known order, a processor configured to determine that the detection of the blood pulse is correct when the detection of the blood pulse by each of the at least two detectors takes place in the known order, and to determine the heart pulse of the person on the basis of the detected pulses that are determined as correct.
